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I have some crazy ideas about some stuff lately but to make it tangible I need a bit more information over the capacitive touch screens.

Is there a way to create an object that can be sensed by a capacitive touch screen without the touch of the human skin?

I mean, imagine a tiny piece of something that you can just lay on the screen and the screen thinks is a finger or a stylus.

I've heard about the stylus that can be sensed, but I think that the skin has to be touching it in order to work.. is it true? Can I maybe create something out of ordinary house stuff that can do this, without the need of the skin to touch it?

Ahh, and by the way, it need to be capacitive because multi-touch is needed.

Thank you all and best regards!

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    I know this isn't what your looking for, but I found (by accident) that a banana (with the peel on) is recognized. :) – Ryan Conrad May 17 '11 at 13:56
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    Voted to close since this is only tangentially related to Android (it equally applies to Windows Phone 7 devices with such screens, for example). It's more of a physics question, though possibly too basic for the Physics SE? – Matthew Read May 17 '11 at 14:03
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    I'd hate to see a question of such obvious relevance to using android devices closed! Where I live, we wear gloves part of the year - having to decide between cold hands or seeing what is going on in the world, or carrying around yet another overpriced, easily lost object such as a purchased stylus is not a great set of choices. – Chris Stratton May 17 '11 at 14:50
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    @Chris capacitive touch screen compatible glove reviews: brighthub.com/mobile/mobile-accessories/articles/90129.aspx ;) – GAThrawn May 17 '11 at 15:21
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    Rumor says, the South Koreans (which also happens to be Samsung's home country) used sausages stylus so they don't need to put off their gloves in the freezing winter. – Lie Ryan May 17 '11 at 15:24
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Yes, capacitive screens just need something that alters their capacitance: something conductive or a dielectric.

As per usual, Wikipedia has more information.

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Here's a video on how to create a capacitive stylus for free (as long as you have an anti-static bag laying around).

From the page:

In this video we show you how to create a free capacitive touch screen stylus out of a common piece of antistatic film. As many people know capacitive touch screens use an electrical impulse created by the operator's body to register a touch point on the screen. The only problem with this is that if you are wearing gloves or need to make a precise touch point, capacitive screens do not work well. Most likely many if not all of our tech-savvy readers have a piece of antistatic film lying around. Simply cut the film to the desired length, roll it up, and (if you want) attach a piece of tape to hold it in place.

  • I'm finding the rolled up film does not work very well - it seems the film really need to be parallel to the screen, which is unfortunate as it makes it hard to get a smaller-than-pinky-finger point. The commercial stylus I saw was also quite fat. Still thinking... – Chris Stratton May 17 '11 at 15:29
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I tried various metal (pins, tubes and foil) and plastic (antistatic bags and foam). I found nothing that was satisfactory. You have some level of control but it is not the same as your bare finger. My advice would be to keep it metal and keep it short. Not all screens are equally sensitive so you have to play around.

I have not tried a commercial stylus.

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